This invention relates to a resinous paste that can be dispensed from a syringe and cured with heat to form a coating or an adhesive. In particular, it relates to a resin paste prepared from a maleimide and a liquid diamine.
Fast curing liquid systems are used extensively in the microelectronics industry as adhesives, sealants, and encapsulants. These liquid systems are typically applied to parts moving on an assembly line and therefore they must be able to cure rapidly. A system must also have a pot life at room temperature that is long enough so that over at least one entire working day its viscosity does not increase so much that it can no longer be dispensed. In addition, of course, it must provide good adhesion to various types of materials. High thermal stability at temperatures above 200.degree. C. is also required in order to withstand downstream processes such as wirebonding. Low water adsorption is desirable so that blisters do not form on heating.
At the present time, epoxy resins are often used for these applications. While epoxy resins have good adhesion, they tend to be rigid and often crack and fail on temperature cycling. In addition, they are not re-workable because they do not remelt upon heating.